Thank you for your help! It is starting to look more how I would like. The code will make the photos on the home page have a background but I still cannot modify the background color of individual text within posts. Is this possible?

You change color on text in individual posts from within the post editor as you create them by highlighting the text you want to change and then using the text color button on the lower row of editor tools in the post editor (row 2, #4).

Don't get too carried away with changing text color or use a bunch of different colors within posts as that decreases readability and comprehension and will drive some people away. When I find such posts, I don't bother reading them at all.